Grinding-machine.



0. 'sA WALKER.

GRINDING MACHINE. APL'ICATION FILED GCT. 22. l9l4.

Patented Dec. 7, 1915.

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3 SHEETS-SHEET I.

0. S. WALKER. GHINDIN'G MACHlNE. APPLICATION FILED OCT.2Z, I9I4`Patented Da. f7, 19I5.

3 SHEETS-SHEET 2.

0. S. WALKER..

GRINDING MACHINE.

APPLICATION HLED oc. 22. r9.4.

Patented Da. 7'-, 1915.

iirrn Yrr rre- OAKLEY S. WALKER, OF WORCESTER, MASSACHUSETTS, ASSIGNORTO O. S. WALKER. CO., OF WORCESTER, MASSACHUSETTS, A CORPORATION OFMASSACHUSETTS.

Gemplus-MACHINE.

Specification of l)LetzefsPatent.

' Patented Dec. '7, i915.

Application :filed October 22, 19111. l Serial No. 868,106.- p

To all whom it may concern.'

' Be it known that I, OAKLEY S. ViiLii-niz, a citizen of the UnitedStates, residing at lVorcester, in the county of lVorcester andCommonwealth of Massachusetts, have invented a new and usefulImprovement in Grinding-Machines, of which the following,`

together with the accompanying drawings, is a specification.' l 1 Thepresent invention relates togrinding?, machines and has particularreference to a rotative movement, -in ordei'to bring all` portions/ofitssurface into contact with the rotatingabrasive element, 'I or have atraversing movement toward and from the axisof rotation. ofpthe-work inorder that all portions'of the? su f be acted upon, with'the ,resultthat.rthepath'v of action of the 'abrasive elementen ,face`v of the worktakes .the form' of a spiral, as A will be readily understood.

With a uniform speed of rotation of the work, and a uniform traversingspeed of the abrasive element thcreacross,',it willfbe apparent that thecharacter of -the abrasive cut will vary across the 'entire face of thework, from the `c enter of rotation toits outside edge, owing to thedifference -in linear speed of points at different distances, from saidaxis of rotation. Obviously, the ground surface near saidcenter will beof a different character than the same area of ground surface near theperiphery of the,l work, owing to the relatively longer period duringwhiclij said centrally disposed sur-v face is in contact with theabrasive element.`

Furthermore, in addition to the noii-uniformity ofthe finished surfaceabove described, machines of this character have 'heretofore beenoperated at the serioi'isdis-l tation a'iid uniform traversing speed ofthewheel, the actual area ground in a given grinding wheel, the latterbeing mounted.` so'` as toi,

interval of time decreases as the wheel approaches the center ofrotation of the work. The present invention aims to overcome 'thedefects in existing machines of this class, by the-elimination of thepractical diii'iculties above enumerated; its objects are embodied inthe production of a lmachine v-having a uniform abrading action withrespect to all portions of the surface of the `work, thereby securing aground surface ,of 'vabsolute uniformity, and also the produc- /tion ofa machineof this character -capable ofoperating at all times at theutmost limit of its'v efiiciency, thereby rshortening appreciably thetime required to grind a surface of agivenarea, over other machinespreviouslyaised for such work.

" Other objects land ladvantages will appear frm H,the followingdescription, taken in connectim with the accompanying drawings, in.which-- 4 Figure 1'.,is a front View o f a machine embodyii'i'gmyinvention. Fig.f2 is a simi' .lar enlarged view of thesame, withportions of the' inclosingl casing removed to disclose 'the'interiorworking parts.`v 3 is a fragmentary cross-sectional view of a portion ofthe machine. Fig. 4 is a fragmentary rear -view of a portion of themachine, viewed from the right hand side ofFig. 3. Fig. 5 is a view,partly in section, of an adjustable stop device. Figs. 6 and 7 arefragmentary vend elevational and sectional views, respectively, of animproved mechanism for adjusting the angular position of the worksupporting means of the machine.

Like reference characters refer to like parts' throughout the differentfigures.

Referring to the drawings, and' in pai'- `ticular to Fig; l, the numeral1 indicates a hollow stand or framework within and upon ing-a slidingmovement in vertical ways 6 carried by the framework. The bracket 5 isvertically adjustable by means of a ver.

tical screw shaft 7, havingthereon a bevel gear 7 i meshing with a bevelgear 8 on the horizontal shaft of a hand wheel 8, by the rotationofwhich thevertical movement of the' bracket is effected, in the usualmanner. Said shaft of the hand wheel carries a sleeve 9 on which ispivoted a swingingtable 9 having journaled therein, and supported in astep. bearing 10 thereof, a vertically disposed rotatable shaft 11,carrying on its upper end thework supporting and holding means of themachine.' The latter in the present instance is shown Vas a magneticframework 1 have forwardly disposedportions 17 extending approximatelyas far las the centerof rotation of the work, so'

that said guideways 15, 15, overlie theinner half of the work supportingmeans, and, by means of their extension in this manner, enable the ramto be supportedthroughout its entire length, when the same is at thelimit of its forward stroke, as shown in Fig. 1. The ram` 16 has a.central depending bearing 1S disposed to move between the forwardportions 17 of the framework, as shown in FigfS, said'bearings servingfor the support of va rotatable shaft 19', which carries on its forwardend a grinding wheel 2O partially surrounded by a suitable sta'- tionaryshield 21. In thereciprocation of theram 16 the wheel 20 moves in andout between the forwardly extended portions 17 of the framework 1, sothat it is afforded a rigid and unyielding support in all positions. Anelongated pulley 2 2 carried by lthe shaft 19 has a belt connection witha pulley 23 carried on the driving shaft 2,

4providing for the rotation of the grinding Vwheel at a constant rate ofspeed in any position assumed by the ram 16.

The driving shaft 2 also carries a stepped pulley 24 having a beltconnection with a corresponding stepped pulley 25 on the driv ing shaftof a speed accelerating mechanism suitably supported within theframework 1. Said speed accelerating mechanism is shown in the presentinstance in the form of the well known Evans drive, and comprises afrusto-conical driving pulley 26 and a similarly shaped driven pulley27, the two pulleys being oppositely disposed one above the other, andhaving their peripheral surfaces spaced apart slightly to receivevbetween .them a loose endless belt 28, the thickness of varies thedriving ratio between them at each increment of such movement, with vthebelt in the position shown in Figs. 1 and 2, the driven shaft 32carrying the pulley 27 has imparted thereto a relatively rapid rotationfrom the uniformly rotating driving pulley 26, but as the belt isgradually moved to the right the driving ratio is decreased, and at thelimit of right hand movement of said belt, the driven shaft 32 is causedto rotate at a slower speed than the uniformly rotating driving pulleyas will be clearly understood.

'zol

y At its forward end the shaftA 32 has an operative connection with ashort horizontal shaft 33, carried by the table 9, and serving, by meansof intermeshing bevel pinion 34 and gear 35, to rotate the shaft 11which carries the work supporting and holding means l2. To compensatefor the vertical and also the swinging movement of which the table 9 iscapable, this operative connection preferably consists of a pair of teleseopic shafts 36 and 37, splined together to rotate iii-unison andhaving universal 'joint connections 38 and 39 at their opposite endswith the contiguous ends of the shafts 32 and 33. By the means abovedescribed, the work supporting and holding means 12 is caused to rotatein synchronism with the variable. speed shaft 32. At its other end theshaft 32 carries a stepped pulley 40 having a belt connection with acorresponding stepped pulley 41 on the end of a shaft 42, supported forrotation in the upper end of the framework. The shaft 42 has oppositelyfacing loosely journaled beveled pinions 43, 44 thereon, the hubs ofwhich present oppositely facing toothed clutch surfaces 45 and 46,respectively, adapted to be engaged selectively by a slidably mountedclutch collar 47, keyed to rotate with said shaft 42. The bevel pinions43 and 44 are in mesh 'with a bevel gear 48 on dialnetrically oppositesides of the latter; the movementof the clutchA collar 47 to lock thepinion 43 to shaft '42, causes rotation of gear 48 and its shaft 49 inone direction, while the movement of said clutch collar to lock thepinion 44 to the shaft 42 causes rotation of the gear 4S and shaft 49 inthe opposite direction.

Vll'hen the collar 47 is moved to its intermecarries arpinion 50, inmesh with an idle.

' gears serving to drive shaft 53 at a greatly reduced speed from shaft49. A pinion '54 carried by said shaft 53 meshes with al rack bar 55secured to and depending from the under side of the ram 16, whereby thesliding movementof said .ram in its ways 15, is etlected. The pinion 54is made long enough to remain in mesh with the rack in spite of thelongitudinal movement of which the,

shaft is capable, inorder to carry the gear 52 into and out of mesh withgear 51, as shown in full and dotted lines, Fig. 3. To provide for thislongitudinal movement of shaft 53, the outer bearing 56 of the samecarries a pin 57, the rounded end of `which is held yicldingly withineither one of apair of spaced annular recesses 5S or 59 by a lightspring (S0. 'hen -the shaft 53 is forced inwardly, bringing the recess59 into operative relation, t-he connection of said shaft with thesource of power is destroyed, leaving it free to be rotated by a handwheel 61, to effect the movement of the ram 16 in t-he desireddirection..

The ram 1G on its upper side has a longitudinal undercut groove (32.inwhich a pair` of movable stop blocks (33 and (S4 are capable of beingheld, by their retaining nuts G5, in any desired position of adjustment,one on each side of a substantially vertical arm 66 of a four arm lever,pivoted' at (37 to the inside of the framework. A depending arm (58 ofsaid lever is forked at its end, and provided with oppositely extendingcontact screws 69, (39, adapted to engage on opposite sides of aprojection 70 of the clutch collar 47, to move the latter in onedirection or the other, in response to the `contact of one or the otherof the stop blocks 6364 with the vertical arm 66 of the lever. Anotherarm 71 of said lever has a rounded end in engagement with the taperedend of a spring pressed pin 72, carried in a suitable socket'- on theframework, and adapted to yieldinglyretain the clutch collar in 'each oftheA operative positions into which it is moved by the lever, until thevertical arm 66 isengag'ed .ram by'the size of the work.

64, depending upon. the direction in which the ram is moving, effectsthe movement of the clutch collar 47 to reverse the rotation of'thebevel gear 4S, as previously described, and through the connectedgearing, to reverse themovement of the ram 16. In the positionof theparts shown in Figs. 1 and 2 the stop block 64 has just moved the arm(S6 to the left, effecting the movement of the clutch collar 47 to theright and causing the rotation of the gear 4S to be imparted by thepinion 43. As a result the ram 16 has just begun its traversing movementtoward the right, and it will be noted, is moving at its greatest speed,due to the illustrated'position of the belt .28 between the two cones ofthe Evans drive. The ram moves ,with constantly decreasing speed towardthe right until the stop block 63 forcibly en` gages the arm 6G to shiftthe clutch collar toward the left, causing the pinion 44 to besubstituted for the pinion 43 in the drive of the gear 48 and therebyreversing the movement of the ram.

The edge of the ram, adjacent the groove G2 is graduated, as shown, at73 and 74 to provide for the proper setting of the two blocks (S3 and64, respectively, in accordance with the length of stroke required oftheThe graduations 73. for use with the block (S3, are employed todetermine the length of travel of the ram away from the center of'rotation of the work, while the graduations 74, for use with the blockG4, are employed to .determine the distance from said center of rotationat which the ram reverses, when moving toward said center.

The stop block 63 has a forwardly eX- tending rod 75, carrying on itsextreme end a loosely fitting knurled bushing 7G. The

outer end of said bushing is recessed to re "rain to the right, is inposition to strike the arm 81 of a bell crank lever S2 at the same timethe stop block 63 engages the vertical arm 66. The resulting downwardmovement of the other arm 83 of said bell crank ydepresses a springpressed pin 84 into the path of a lug 85 carried on' a longitudinalextension SG of the clutch collar 47, the parts being so timed andspaced that the sliding movement of the clutch collar is arrested midwaybetween the opposing toothed clutch surfaces 45 and 46, therebydisconnecting the ram from its automatic drive, and causing it to cometo a stand still at the limit of v yram 16 may be started orstopj'nedvwhende*V its movement away from the center of rota-v tion ofthe work. rllhe fourth arm 87 of the four armed lever has a. projectingknob 88 which furnishes a manual means bywhich the operation of theautomatic feed lfor the sired.

set forth, is capable of'beingtransmitted to drive the rack 30, by meansof which the belt 28 of' the speed accelerating mechanism, or Evansdrive, isrecipr-ocated` To this end said shaft carries a gear' 89, inmesh with a gear 90 carried upon a'stub shaft 91, which is journaled ina box on an arm 92, pivotally suspended from the Shaft 53- The shaft 91carries a pulley 93 having a belt connection with a. pulley 94 on a stubshaft 95, the inner end of which carries a gear 96 in mesh with theteeth of the rack 30. The reversals 0f the travel of belt 28 are therebyrendered simultaneous with the reversals of travel of ther ram 16. Whendesired, however, the

speed .varying feature of the machine may be dis ensed with, byrendering ineffective the bet connection between the pulleys A93- and94, as shown in Figs. 3 and 4, the shaft 91, which is carriedupon theswinging arm 92, extends through an elongated segmental vslot 97 in therear'side 14 of the framework, and the free' end of said arm has ahorizontal projection 98 extending through a. second elongated segmentalslot 99 ingsaid framework. ABy means of a knob 100, screw threaded onthe outer end of said projection 98, and bearing against an interposedwasher 101, the arm 92 may be retained at the limit tof'its swingingmovement to the right, Fig.'

4, to hold the belt tight, but when said knob is loosened, the tensionof the belt necessary to furnish a driving connection is destroyed.

To enable the arm to be swung in the direction to create a drivingtension, the washer 101 has an extension 102 in convenient p0- sition tobe seized by the operator.

The table 9 has been previously described as being capable of swingingmovement with respect to the bracket 5, in order to provide for theinclination of the work holding face of the chuck 12 when a concave orconvex grinding operation is desired. As shown in Figs. 6 and 7, thelower end of the bracket 5 is formed with a shallow boss 103, .having afinished surface, against which is normally disposed a hardened steelplate 104, pivoted at 105, and having a depending finger 106 by means ofwhich it may be moved into and out of its normal position. The table 9carries on its lower end an inwardly projecting screw 107, constitutingka spacing means of vfixed and predetermined length, adapted when incontact with the face of plate v104, to insure the exact horizontaldisposition of the face of the chuck 12. The

The rotation of the shaft, same be power or hand driven, 'as'previouslytable 9 also carries an adjustable screw 108, above and to one side ofthe fixed screw 107, the end of the said screw 108 adapted to engage thesurface of the boss 103 at one side of the plate 104. The swinging ofthe plate 104 out of the path of the screw 107, rendering the lattermoperative, enables the table graduations of a suitablescale 113, ofthe' type ordinarily provided for this purpose. By the provision of theparts above described, it will be apparent that the horizontal positionof the chuck face, once determined, is'easily and accuratelyreestablished, whenever desired, and moreover, is made entirelyindependent of the scale 113, with the result that any errors in saidscale, or any Achance for inaccuracy on the part of the operator insecuringa nice adjustment thereon, are entirely eliminated.

To one skilled in the art to which this invention a'ppertains, theadaptability of the machine to many forms of surface grinding, andparticularly t-o disks or annular plates, will be readily apparent fromthe foregoing. The synchronous .acceleration of .the rotating work, andthel traversing head or ram, as the abrading element carried by thelatter approaches the center of rotation of said work, insures theproduction ofva uniformly ground surface, it being a requisitecharacteristic of the change speed mechanism or Evans drive that theproportions of the latter are such as to insure the submission ofsubstantially equalv areas of the surface of the work to the a'ction ofthe Wheel 20, in equal increments oftime during its traverse in bothdirections. In other words, the resultant of the two factors whichdetermine the character and extent of the abrasive action, namely thelinear speed of the work and the traversing speed of the abrading ele-"ment, is kept substantially constant during both the forward andreverse strokes of the ram. Assuming, as is perfectly proper, a

adjustment of the stop blocks 63 and 64 with iespect to their associatedgraduations 73 and 74, the eXtent of the traverse of the -ram may beeasily and quickly limited to the radial extent of the work, aswill bereadily understood. I l

It will be apparent, also, that the above described relation between therotative speed of the work and the traversing movement of the abradingwheel, is maintained at all times, irrespective of whether the ram 16 beautomatically driven from the power shaft, or not. `When the shaft 53 ismoved longitudinally inward, to render the hand wheel 61 effective formovement of the ram, the interdependence between the position of saidram and the position of the belt 28 is not thereby destroyed, and as aresult, the rotative speed of the work still increases or decreases asthe ram is moved, by hand, toward or from the center of rotation.

As hereinbefore set forth, the belt connection between the shaft 58 andthe driving pinion 96 of the change speed mechanism, or Evans drive, maybe rendered ineffective, when desired, thereby permitting the rotationof the work at a constant speed, which is determined by the positionwhich the belt 28 is caused to assume. Under these conditions, andparticularly when the ram 16 has been disconnected from its automaticfeed by endwise movement of the shaft 53, the proper relation betweenthe traversing positions of the ram 16S-and belt 28 is wholly destroyed,with the result that when the automatic feed of the ram is restablished,and the aforesaid belt drive for the change speed mechanism is againrendered effective, it is highly probable that the belt 28 and ram 16will not reach the end of their corresponding strokes simultaneously, asshould be the case. This contingency is provided for in a pair ofpositive stops 114 to limit the movement of the rack 30 in eachdirection, and this action is made possible by the use of a non-positiveor belt connection between the pulleys 93 and 94, which slips on saidpulleys, until the aforesaid proper relation is restablished.

l claim,

1.' ln a grinding machine, a fixed framework having a portion thereofoverhanging the work to be operated upon, and an abradmachine, a fixedframe hanging said work supporting means, and an abrading elementsuspended below said overhanging portion and slidable longitu= dinallythereof.

et. In a grinding machine, a rotatable work'supporting means, anabrading means having a traversing` movement toward and from the centerof rotation of said work supportingl means, and means for acceleratingthe speed of said work supporting means, as the abrading meansapproaches said center of rotation.

5. ln a grinding machine, a rotatable work supporting means, an abradingmeans havinga traversing movement toward and from the center of rotationof said work supporting means, and means for synchronously acceleratinglthe rotation of said work supporting means and the movement of saidabradin-g means as the latter approaches the center of' rotation of saidwork supporting means.

G. In a grindingmachine, a work traversing abrading means, means forrotating the work during the action thereon of said abrading means, andmeans for maintaining` constant the area of the surface of the worksubmitted to said abrading means in successive like intervals ofv timeduring the .period of the traverse of said abrading means. y

7. In a grinding machine, means for rotating the work to be operatedupon, means for traversing the surface ofv said work with an abradingelement, and automatic means for maintaining the abrasive action of saidelement substantially constant with respect to successive intervals oftime during the period of its traverse over said w'ork. v S. In agrinding machine, means for supporting the work to be operated upon,means for traversing the surface of said work With an abrading element,and means for rotating said work supporting means at variable speeds,whereby to present substantially equal areas of the surface of said workto the action of said abrading element during like increments of time.

9. ln a grinding machine, means for rotating the work to be operatedupon, an abrading element adapted to have a traversing movement towardand from the center of rotation of said work, and means for moving saidabrading element at varying speeds, whereby to act upon substantiallyequal areas of the surface of said work in like i11- crements of time.

10. In a grin-ding machine, a work supporting means, van abradingelement having a traversing movement with respect to said worksupporting means, and means for rotating said work supporting means atvarying speeds, as determined by the radial distance of said abradingelement from the center of rotation thereof.

11. Ina grinding machine, a work supporting means, an abrading velementhaving a traversing movement with respect to said work supporting means,and means for rotating said work `supporting means at speeds inverselyproportional to the radial distance of said abrading element from thecenter of rotation of said work supporting means.

12. In a grinding machine, means for rotating the Work to be operatedupon, means for traversing the surface of said Work with an abradingelement, means for accelerating the rotation of the work and thetraversing movement of the abrading element as4 the latter approachesthe center of rotationl of the Work, and means for maintaining apredetermined relation between the rotative speed of the Work and thetraversingl position of said abrading element when the latter isdisconnected from said accelerating means. 4

13. In a grinding machine, means for rotating the Work to be operatedrupon, means for traversing the surface of said 'Work withl an` abradingelement, an automatic accelerating mechanism effective jointly upon therotation of the Work and the traversing movement of the abradingelement, means for .disconnecting said abrading element from saidautomatic accelerating mechanism, andA means for thereafter controllingthe action of said automatic accelerating mechanism in response to theVtraversing position assumed by said abrading element.

y 14. In' a grinding machine, means for rotating the Work to be operatedupon, an abrading element capable of a traversing movement toward. andfrom the center of i rotation of Sa'id Work, adjustable stops lfor i vment of said abrading element in each direcdetermining the extent oftraversing movetion, and a graduated scale, associated with each of saidstops, for determining the position of said stops with reference to theouter and inner diameters respectively of the rotating Work.

'15. In a grinding machine, an abr'ading element having aI reciprocatingmovement with respect' to theV work to be operated upon, stops operable`at the end of the stroke of said element in each direction to effect areversal of its movement, and means carried by one of said stops, andmovable into a fixed position with respect thereto, for effecting thedisconnection of said abrading element from its driving power at the endof its movement in one direction.

16. In a grinding machine, an abrading element, having a traversingmovement With respect to the surface of the work, means for reversingthe movement of said abrading element at each end of its stroke,comprising .i a clutch member movable into two different operativepositions, adjustable blocks carried by Said abrading element foreffecting the movement of said clutch member, and means carried by oneof said blocks and movable into a fixed position with respect thereto,for stopping said clutch member in an intermediate inoperative positionat the end of a Stroke of said abrading element.

17. In a grinding machine, a work supporting table capable of swingingmovement to vary the inclination of its work supporting face, and meanscooperating with said work supporting table for insuring the horizontaldisposition of said work supporting face, said means being movable intoan inoperative position to'permit the adjustment of said table for otherpositions of said face.

18. In a grinding machine, a fixed framework, a member pivoted thereto,a work supporting-tablecapable of swinging movement to vary theinclination of its work supporting face, means carried by said table forcontact with said pivoted member when said worksupporting face is in ahorizontal plane, and adjustable means, operative upon the movement ofsaid pivoted member into inoperative position, for securing thedisposition of said work holding` face in planes inclined from thehorizontal.

19. In a grinding machine, an abrading element having a path of movementacross the Work to be operated upon, mechanism for moving said elementat varying rates of speed in a predetermined relation to its positionwith respect to said work, means for disconnecting said element fromsaid change speed mechanism, and means for insuring the restablishmentof the same relation betvv-een said element and said change speedmechanism when they are thereafter operatively connected together.

20. In a grinding machine, an abrading element having a path of movementacross the Work' to be operated upon, mechanism for` reciprocating saidelement at varying speeds in response to its position with respect tothe work, means for rendering said change Speed` mechanism inoperative,and. means for insuring the restablishment of \the same driving relationbetween said ele ment and said mechanism when said mechanism isthereafter rendered operative.

21,. In a grinding machine, an abrading element having a path ofmovement across the work to be operated upon, mechanism forreciprocating Said element at varying speeds in a predetermined relationto its position with respect to the work, said mechaniSm comprising africtional driving member reciprocating in synchronism with saidabrading element, a non-positive driving connection between said changespeed mechanism and said abrading element, and means forlimiting themovement of said driving member'in either direction, whereby to in-'sure the maintenance of the` relation between therein, a member sldablein said ways, and the position of the abrading element and the anabradng element suspended 'from said position of the driving member.member in the space between said ways.

22'. In a grinding machine, a work sup. 4 Y OAKLEY S. WALKER. 5 portingmeans, a fixed framework having a Witnesses: v

portion overhanging said work supporting PENELOPE COMBERBAGH,

means, and .providing spaced parallel ways NELLIE lVVHALEN.

